The field of fiber optics has greatly expanded, largely in response to the constantly increasing demand for greater bandwidth in the telecommunications industry. New telecommunications pathways are created—and old ones replaced—as fiber optic lines are installed all over the world. This activity has led to a high demand for cable installation and maintenance services as optical fiber cables are increasingly preferred over copper and other analog telecommunications pathways.
Optical fiber cables are generally composed of one or more optical fibers, also referred to as simply “fibers” or “strands,” and commonly carry many optical fibers. Each fiber consists of a transparent core, or bare fiber, through which optical data signal modes, or light signal modes, may travel. The manufacturing method and particular makeup of a core can vary amongst manufacturers and applications. Regardless, each fiber core acts as a waveguide for one (referred to as single-mode fibers) or more (referred to as multi-mode fibers) modes. The fiber core is coated in a protective optical cladding that, in conjunction with the fiber core, utilizes the effect of total internal reflection to confine light signals to the fiber core and transmit them along the fiber's axis.
The cladding is in turn coated in one or more buffer layers or protective coatings for increased protection from moisture and physical damage. In some applications, multiple fibers are contained within one or more buffer layers or coatings, while in other cases a plurality of fibers with buffer layers or coatings are contained within a larger buffer layer or coating. In both circumstances, the encased group of fibers is referred to as a fiber “tube,” or “bundle.” In most applications, multiple fiber bundles will be encased in at least one jacket layer as well, forming the complete optical fiber cable. Fiber cables in general may also contain various strengthening members, such as mesh sleeves or semi-rigid cores, as well as various coatings, buffer layers, and jackets depending on the specific characteristics required of a fiber cable for a particular application.
Generally, the most predominant forms of commercially available fiber cables come in one of two configurations. In the first configuration, the cable is composed of 12n fibers, where there are n number of fiber bundles each containing 12 fibers. These cables are often referred to as 12-strand tubes. The 12-strand tubes each are composed of 12 fibers wrapped in at least one buffer layer. A fiber cable utilizing n 12-strand tubes will therefore be comprised of 12n fibers.
Similarly, another somewhat common configuration utilizes 6-strand tubes wherein each tube contains six fibers. Therefore, a cable utilizing n 6-strand tubes will be comprised of a total of 6n fibers. While any configuration is possible, those utilizing one or more 6- and 12-strand conduits within the cable jacket are the most prevalent. Regardless of the configuration, fiber optic cables are comprised generally of fiber cores surrounded by a cladding layer, with one or more of such fibers coated with or sheathed in a protective buffer layer to form a fiber bundle. Covering one or more such fiber bundles with one or more protective jacket layers then forms a typical fiber optic cable. Optical fiber cables thus commonly have, for instance, 12, 24, 48, 96, 216, or 432 individual optical fibers, or other such combinations.
Two optical fiber cables must frequently be joined end-to-end to form a continuous optical waveguide. Cable splicing is performed, for example, when laying new optical fiber cables. Contiguous sections of optical fiber cable are joined together at their abutting, or proximal (relative to the joint), ends to form a continuous complete cable between their distal ends. Cable splicing can, for example, permit the installation of optical fiber over great distances and around obstacles and turns in the cable path.
During splicing activity in which two fiber optic cables are spliced together to form a continuous waveguide, a splice protector having a strengthening member is usually secured around the spliced joint to add strength and rigidity to the joint. The splice protector is sometimes referred to as a splice tube, a splice connection sleeve, a splice protection sleeve, or simply a splice sleeve. The strengthening member is often made of metal or alloy, but may also be made of plastic or other elastic or pliable material. It adds rigidity to the spliced joint in order to decrease the amount of potential flex that can occur at the interface of the proximal ends of the cable members when one member experiences movement relative to the other. Such movement exerts stress on the splice joint, potentially damaging the connection and reducing, impairing or terminating the ability of data signals to traverse the joint with minimal loss, attenuation or degradation. The strengthening member protects the integrity of the splice joint by absorbing unwanted forces and maintaining the positioning of the optical fiber proximal ends relative to one another.
Splice sleeves are normally comprised of an inner fiber tube, a strengthening member, and an outer shrink tube. The inner fiber tube is often made of a flexible, dielectric material and is the splice sleeve element through which the joined optical fibers pass. The outer shrink tube encompasses the inner fiber tube and strengthening member. The strengthening member is positioned between the exterior of the inner fiber tube and the interior of the outer shrink tube.
To splice the proximal ends of two contiguous optical fiber cables, it is common practice to strip the outer cable jackets and protective coatings to access the one or more fiber bundles. Each fiber bundle exterior is then stripped to gain access to the fibers themselves, if necessary, and cladding is removed from the cores. The fibers at the abutting end of one of the two contiguous cables are matched to the corresponding fibers at the abutting end of the other cable to form a fiber pair. One fiber in each fiber pair is threaded through a splice sleeve before the fiber pair is spliced together.
Each fiber pair is then prepped for splicing by cleaning the fiber, stripping the fiber cladding (if not previously done), and cleaving the ends of the fiber core. The fiber pair is then spliced together and the optical characteristics of the joint are tested to ensure that the splice was carried out successfully. Upon the confirmation that the splice has been completed successfully, the splice sleeve is positioned over the splice joint. Heat is applied to the splice sleeve to shrink or melt the outer shrink tube to the fiber, splice joint and other splice sleeve components.
The current methods of optical fiber cable splicing present several unsolved problems. As various fiber pairs are in the process of being prepped and spliced, natural movement and jostling of the fiber pair being attended to can often cause the remaining optical fibers in the bundle to shift and move about the workstation. This can have several negative consequences, such as the remaining fibers becoming tangled or broken. These fibers can also come into contact with substances present on the workstation, contaminating them and potentially causing undesirable optical characteristics, decreasing the longevity of the spliced joint, or it can simply create further cleaning work for the installers, increasing the installation time and cost. Substances used in the splicing process or from the interior of the optical fiber cables used to clear the interior of any moisture will often be present on the workstation surfaces and can contaminate stray fibers that have shifted out of position.
The problems caused by shifting fibers can also be magnified when one or more unsuccessful attempts are made when stripping or cleaving the fiber. Multiple attempts at stripping and cleaving can result in some fibers being shorter relative to the terminal ends of other fibers in the bundle. This can occur relatively between fiber bundles as well. Splicing a shortened pair will draw the longer pairs closer together and create slack in those corresponding fibers. This can exacerbate the problem of fibers becoming tangled, contaminated or broken due to movement.
The movement of the fibers as described above also poses a significant increase in the time expended when splicing two cables together. For example, for the fibers that have not yet been spliced to their corresponding match, such movement can cause the splicing sleeve that has been pre-threaded to slide off the fiber onto which it was placed. The splicing sleeve must then be retrieved, checked for contamination or discarded, and be placed back onto the fiber or replaced with a new splicing sleeve. This can occur several times over the course of the splicing activity for each fiber pair, leading to considerable decreases in productivity and increases in a project's material waste.
Furthermore, each joint must cool after the splice sleeve is heat shrunk around the joint for a cooling interval. The shrunken material exhibits adhesive characteristics before curing (i.e., cooling) occurs. Known systems and methods of splicing often result in many joints sticking to one another as the cables are spliced together, and can require undesirable forces to be applied to separate the individual joints prior to placement in the workstation retaining structures.
Therefore, given the current state of the art, there exists a need for an apparatus that may be used during splicing activities to organize fiber pairs and restrict their unwanted movement, while maintaining accessibility to those splicing fibers together. Such an apparatus would be helpful in increasing productivity and decreasing material waste and frustration while splicing and preventing contamination of the fibers, thereby negating unnecessary cleaning, retrieving, and rethreading actions.